Hydraulic apparatus



Oct. 29, 1957 L. BAINES ETAL HYDRAULIC APPARATUS 2 Sheets-Sheet 1 Filed Dec. 4, 1953 INVENTORS I Leslie Baines and Leonard S. 'Barnfish BY 012M, wmm m ATTORNEYS Oct. 29, 1957 L. BAINES EIAL 2,811,143

7 HYDRAULIC APPARATUS Filed Dec. 4, 1953 2 Sheets-Sheet 2 4 FIG. 9 6

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"we/wow I Les-He Bines and Leonard S. Barnish er HM. wmwlm Yam ATTORNEYS United States Patent APPARATUS Leslie Babes and Leonard Sinclair Barnish, Wakefield,

England, assignors to Richard Sutcliffe Limited, Wake- ..fiel n n Application December 4 1953 Serial No. $9 6,262 4 Cl imsl.- 121- 1) his. i v nt on lates t hy r ulically operated .drivhis uni and h s pa ticular al h ugh n t exclusive reference to hydraulically operated driving al lit .for con.- veyors,

It is an object of the present invention to provide a hydraulically operated driving unit .of improved design which is capable of eflicient operation at low speeds.

According to the present invention a hydraulically .operated unit comprises a stator having at least one set of cylinders and pistons an a rotor with internal cam s re faces which co-operate with the cylinders 0r pistons so that reciprocation of the cylinders or pistons produces rotation of the rotor.

In a preferred embodiment of the invention suitable for driving a belt conveyor the stator is made of a number of sections mounted'on a shaft and formed with five or more or less sets of cylinders equally spaced around and projecting radially from its circumference. That shaft is hereinafter referred to as the main shaft. The sides of the cylinders of each set are slotted to accommodate a cross shaft against which bear pistons movable Wi hin the cylinders. The axis of each cross shaft is parallel with that of the main shaft and each shaft carries one set of bearings.

The bearings travel in cam tracks arranged internally of a hollow drum member which surrounds the main shaft and forms the rotor. The flow of hydraulic liquid to and from the cylinder is controlled by rotary valves mounted for convenience at each end of the main shaft.

As an example of the invention a driving unit suitable for a belt conveyor will now be described in greater detail with reference to the accompanying drawings of which:

Fig. l is a cross section of part of the driving member, and

Fig. 2 is a further cross section showing in part a control valve and cylinders.

The driving member has a stationary main shaft 1 with five sets of cylinders equally spaced around the circumferences of a stator 2 and projecting radially therefrom. One set only is shown in Fig. 1. Each set contains four cylinders 3 which are arranged so that one cylinder is adjacent each end of the shaft 1 with two cyl inders at the centre. Each cylinder in each set is diametrically slotted for about one half of its length to accommodate a cross shaft 4 of which there are ten, two for each set of cylinders each arranged with its axis parallel to that of the main shaft 1. Slidable within each cylinder is a piston 5 whose head bears against that part of the cross shaft 4 inside the cylinder. The pistons are hollow and have deep skirts.

The cross shafts 4 are generally of circular cross section except for those portions 6 which lie inside the cylinders where the cross section changes to rectangular.

Between the outer and central cylinders each cross shaft carries a bearing race containing for example, roller bearings 7 and the outer race 8 of which bears against 2,81 1,143 vPatterned Oct .22, 1957 ice a trac ha me an th internal n taee o .e enter in t e form ofa hellew drum .1!!-

Ihe $111 10' e es the assemb y of ma n shaft and ro s sha t nd s m unted on the farm r by hall hearu ll held be een s a o .2 m ilnt d h th ,main haft a ea h nd thereof and ih emelly ex ending flanges 12 o t d t h d um at each en Also ha ed to the h eraal flanges 1. telreta v' inl t an exhaust v lves 13. 1 (o y 91. 6 of eah of appear is Fla wh ch 9; h d l gs 5,1 n he tator so that one controls h d h eh and th e her the e haust :o hydra lic iq id f,.d to the evlinele s, To protect the eempeaehts s de th drum he latter has t o urther in ernal .flaneee 16 bolted with the flanges 12h) the drum 1.0 and whi h of which he closely rolled the tate: a d has an internal pocke wh eh the a flex ble seal any suit ble yp Each et 9. cylinde s ha its own passa e 5 i the t tor 2.. for exa'h h e figu e 1 shows that pa sage 15 is ass. 1 ith th cy ind s Figur shows other pas. a- 5g. .5.d, ea h o wh h i ass e ated wi h one f the eth r s ts h evllhslers inlet 1. .41 an ehsl ihe hhe 'ils mount d on he main.

' ha t a hhu er roove 13s to an ut et pe t 4 and that one of the passages in the stator i line ith h s pert- The es ahs alve 14 .is c nst cte in. e m nn ridem liquid is admitted to each of the sets of cylinders in turn and after a predetermined interval exhausted from each of the sets of cylinders.

The cam tracks 9 inside the hollow drum 10 are elliptical so that as hydraulic liquid under pressure passes into the sets of cylinders the pistons are forced out and the drum is caused to rotate and so drives the belt of a belt conveyor which passes over its external surface.

It will be appreciated that the belt is driven directly thus avoiding drive couplings and speed reduction units as the speed of rotation of the drum can be very low and can be varied by variation of the volume of liquid delivered to the cylinders. In addition the driving power of the unit may be changed by altering the pressure of the liquid delivered. Reversal of the direction of rotation is achieved by reversing the application of the hydraulic fluid.

Any number of drums as described above can be assembled into a multi-drive head. Such a head would continue to drive even if one unit thereof failed. The hydraulic liquid can be supplied from one central pump or each unit may have its own pump. The pump or pumps may be positioned some distance from the driving head as working or installation conditions required. A relief valve may be fitted to the hydraulic supply system to prevent damage due to overloading.

The shock load on a belt due to the starting is very much reduced with the driving unit as the change from start to full speed can be made very gradually.

For ease of manufacture the stator 2 may be built up of a number of sections which are fixed to a main shaft by a key or by any other suitable means (not shown). Conveniently each section may contain one cylinder of each set joined by webs 19 as illustrated in Figure 1. Obviously the size and power of the driving unit can be increased by increasing the number of sections.

The invention is not restricted to the exact construction'illustrated, but what we claim'and desire to secure by Letters Patent is as follows:

1. A hydraulically operated driving unit ,comprising a stator having a plurality of sets of power developing means arranged radially, each set including at least two parallel cylinder and pistonassembliejs, one of the members of each set being fixed to the statorand the other heingmova'ble relative thereto, across-shaft for each assembly againstwhich the movable member of the assem-J bly bears, bearings on the cross-shafts, a plurality of passages in sai'd'stator, each passage being in communication with the cylinders'ofa different set of assemblies, and a surrounding hollow rotor, at least one cam surface on the internal face of said rotor forco-operation with said bearings on thecrofss-shafts of the sets of assemblies in the same radial group to cause rotation of said rotor in synchronism with the reciprocation of said movable as: sembly members, control valves secured at each end of the rotor and rotatable therewith to control the admission of exhaust of hydraulicliquid from and man inlet and an outlet member fixed to the stator.

2. A hydraulically operated driving unit comprising a stator having a plurality of sets of power developing means arranged radially, each set including at least two parallel cylinder and piston assemblies, one of the members of each set being fixed to the stator and the other being movable relative thereto, a cross-shaft for each assembly against which the movable member of the assembly bears, hearings on the cross-shafts, a plurality ofpassages in said stator,each'passage being in communication with the cylinders of a diiferent set of assemblies, and a surrounding hollow rotor at least one cam surface on the internal face of said rotor for co-operation with'said bearings on the cross-shafts of the sets of assemblies in the same radial group to cause rotation of said rotor in synchronism with the reciprocation of said movableassembly members, an inlet control valve, an outlet control valve, flanges securing said valves to said rotor at "each end thereof, inlet and outlet members on "said passages in turri.

or 4 I said stator connectable by said control of the assembly, bearings on the cross-shafts, a plurality of passages in said stator, each passage being in communication-with the cylinder-sot a different set of assemblies, and a surrounding hollow rotor, at least one cam surface on the internal face-of said rotor for co-operation with said bearings on the cross-shafts of the sets of assemblies in the same radial group to cause rotation of said rotor in synchronism with the reciprocation of said movable assembly members, control'valves secured at each end of the rotor and rotatable therewith to control the admission of exhaust of hydraulic liquid from and to an inlet and an outlet member fixed to the stator.

4. A hydraulically operated driving unit according to claim 1 in which said control valve is provided with anannular groove to which said hydraulic fluid is admitted,

' 1 References Cited in the file of this patent UNITED STATES PATENTS 835,33'1 "Walker Nov. 6, 1906 1,042,675 Helmes' Oct. 29, 1912 1,087,240 Kellington Feb. 17, 1914 1,455,443' Mayer May 15, 1923 1,533,514 Ragot Apr. 14, 1925' 1,603,969 Michel Oct. 19, 1926 2,371,005 'Wagers Mar. 6, 1945 2,416,940 Morton .Mar. 4, 1947 

